Cedar City

Near this location is a paleosol collection site in the Upper Cretaceous Straight Cliffs Formation used by Retallack in his 2009 study of greenhouse crises of the past 300 million years. Retallack used stomatal index data for fossil Ginko and related leaves as a proxy for past CO2 spikes and paleosol chemical data as proxies for temperature and humidity changes. These data show that global warming due to CO2 rise is a not a unique event in earth history and that the magnitude of the coming anthropogenic greenhouse pales in comparison with past greenhouse spikes at times of global mass extinctions.